1. Field of the Invention
The present invention relates to a charged particle beam apparatus, a defect correcting method, an etching method, a deposition method, and a charge preventing method, and is directed, for example, to irradiation of a beam to a substrate under a low vacuum used in a process of manufacturing an LSI and to correction of a defect in the substrate.
2. Related Background Art
A focused ion beam (FIB) apparatus with an ion source, mainly a gallium ion source, is used to correct defects in a substrate such as a photomask or a stencil mask. It has been recently known that if gallium ions are implanted into a part (glass part) of the photomask which transmits exposure light, so-called gallium stains are caused and decrease the transmission coefficient of the mask, and studies have started on gas assisted etching using an electron beam and various proposals have been made in order to eliminate the gallium stains (e.g., Japanese Laid Open (kokai) 2003-195481 and Japanese Laid Open (kokai) 8(1996)-139079).
However, for example, the disclosure in Japanese Laid Open (kokai) 8(1996)-139079) has the following problems.
(i) When a gas is supplied from a nozzle of a gas supply mechanism to the surface of a substrate, the gas injected from the nozzle diffuses in a vacuum and contaminates a chamber and the inside of an optical column, so that a wiring cable corrodes, and a charged particle beam source deteriorates, resulting in the instability of a charged particle beam.
(ii) It becomes impossible to limit the charged particle beam on the substrate due to the scattering of the beam resulting from the collision between the gas and the charged particle beam, so that the focal position of the charged particle beam is displaced.
(iii) If the gas supply mechanism (nozzle) is disposed in the vicinity of a beam position, nonuniform electric fields are produced in the beam position and its vicinity due to a charge-up caused in the vicinity of the beam position, resulting in an increase in the diameter of the beam and the shift of the beam position due to an aberration.
(iv) Since the gas pressure is high between the surface of the substrate and the gas supply mechanism, an electric discharge is caused between the surface of the substrate and the gas supply mechanism if a high retarding voltage is applied to the substrate or a stage.